JP2019068420A - Distributed antenna system of open flow base - Google Patents

Abstract

To provide a distributed antenna system of an open flow base.SOLUTION: A distributed antenna system (DAS) includes a DAS controller 10 as an open flow controller and one or more DAS unit, in order to dynamically control a traffic transfer policy of a distributed antenna system unit by using an open flow protocol. The DAS controller generates and changes the traffic transfer policy by reflecting the necessity for change request of the traffic transfer policy by an operator's operation or a network support application for defining software and the necessity for change request of the traffic transfer policy due to a state of the DAS unit and a port. The DAS unit reflect the traffic transfer policy received to a data plane surface, and transfers the traffic received on the basis of the polity to a destination.SELECTED DRAWING: Figure 3

Description

  The present invention relates to wireless communication technology, and in particular to a distributed antenna system.

  In Distributed Antenna System, a large number of antennas are distributed in the cell coverage of a macro (macro) radio base station of a mobile communication carrier, and a base station targeting a shaded area where radio waves are difficult to reach Devices that perform the function of amplifying and relaying the signal so that the signal can be reached, but recently, as an additional function, LTE / 3G small cell (small cell) and Wi-Fi (registered trademark) AP etc. It supports the functions of the backhaul transmission network, which can be accommodated.

  The commonly used distributed antenna system statically configures transmission policies in transmitting radio signals, and recently, some vendors dynamically adjust resources based on their own standards. It sells distributed antenna systems with the addition of functions that can be rearranged.

  Software Defined Network (SDN) is a next-generation networking technology that conveniently handles network routing and control and complex operations management through software programming. To this end, software defined networks separate the data plane (control plane) of the network from the control plane (control plane), provide a standardized interface between them, and control the network operator according to various situations. The plane can be programmed to control the communication functions performed in the data plane in various ways.

  The OpenFlow protocol is a protocol mainly used in such software defined networks, and is a protocol that performs various classification, forwarding, bandwidth control, statistical processing, etc. of packets according to the user's policy.

US Patent Application Publication No. 2013/0343755 Specification (disclosed on December 26, 2013) Korean Patent Publication No. 10-2013-0052030 Specification (May 21, 2013) Korean Patent Publication No. 10-2015-0088626 Specification (August 3, 2015)

The present invention aims to dynamically control the traffic transmission policy of a distributed antenna system using an open flow protocol to improve the efficiency of traffic transmission.
Furthermore, another object of the present invention is to enhance the compatibility with other vendor products by using standard protocols.

Furthermore, another object of the present invention is to enhance the function of the distributed antenna system using various functions provided by the open flow protocol.
In addition, the present invention achieves scalability and ease of operation maintenance by supporting a flexible and easily reconfigurable network by evolving to a distributed antenna system that supports software defined networks (SDNs). It is another purpose to do.

  A distributed antenna system according to one aspect includes a DAS (Distributed Antenna System) unit and a DAS controller. The DAS unit is one of a head end unit, a hub unit and a radio unit, and routes received traffic based on a set traffic transmission policy. The DAS controller generates or changes a traffic transmission policy and transmits the traffic transmission policy to the DAS unit in response to a policy setting request from an operator or an SDN-based application.

  According to yet another aspect, the DAS controller periodically checks the status of the DAS unit and dynamically changes the traffic transmission policy upon status change to transmit to the DAS unit.

  According to yet another aspect, the DAS controller receives an event due to a port state change from the DAS unit, dynamically changes the traffic transmission policy, and transmits it to the DAS unit.

  According to the present invention, is it possible to set the traffic transmission policy quickly and efficiently through the integrated SDN support application without having to change the setting in each unit of the distributed antenna system to change the traffic transmission policy? , Change is possible.

Moreover, not only the traffic transmission policy change by the operator but also the traffic transmission policy can be dynamically changed according to the state of each unit and port.
In addition, the use of standards-based protocols allows standards to be more compatible with other vendor products.

  Furthermore, it is possible to provide an open flow based operation management framework that can be applied simultaneously to Radio traffic and Ethernet (registered trademark) traffic.

FIG. 1 is a block diagram illustrating the configuration of a distributed antenna system supporting an open flow protocol according to one embodiment. FIG. 2 is a view showing a frame structure used in the distributed antenna system shown in FIG. 1; FIG. 2 is a block diagram illustrating the configuration of a distributed antenna system unit according to one embodiment. 15 illustrates a process of setting a data plane of a distributed antenna system unit not supporting an open flow protocol according to another embodiment. 12 is a view showing a distributed antenna system policy setting process using an open flow protocol according to another embodiment. 7 is a diagram illustrating an example of traffic transmission of the distributed antenna system according to still another embodiment. FIG. 7 is a table showing an example of set policy information of the distributed antenna system unit for traffic transmission shown in FIG. 6; It is a drawing showing an example of policy change of a distributed antenna system by the other embodiment, and traffic transmission by it. FIG. 9 is a table showing an example of set policy information of the distributed antenna system unit for policy change and traffic transmission shown in FIG. 8;

  The foregoing and additional aspects are embodied through the embodiments described with reference to the accompanying drawings. It is understood that the components of each embodiment can be variously combined within the embodiment, as long as there is no other mention or contradiction. Each block of the block diagram may represent a physical part in any case, but in yet other cases it spans part or more of the functions of one physical part It is a logical expression of the function. Sometimes, a block or part of it may be a set of program instructions. Such blocks may be implemented entirely or partially by hardware, software, or a combination of these.

  FIG. 1 is a block diagram illustrating a configuration of a distributed antenna system supporting an open flow protocol according to an embodiment.

  The distributed antenna system is a system utilizing a plurality of distributed antennas connected to a single base station by wire or dedicated line, and the single base station is located at a predetermined distance or more within the cell serviced by the base station. Manage multiple antennas. It is distinguished from a centralized antenna system (centralized antenna system) in which a plurality of base station antennas are concentrated in a cell, in that the plurality of antennas are dispersed and located at a predetermined distance or more in the cell. .

  Also, the distributed antenna system may be femto in that each unit of the distributed antenna does not own jurisdiction over the antenna area itself, but rather any distributed antenna areas located within the cell at the base station in the cell center. It is distinguished from a cell (Femto cell). It is also distinguished from multi-hop relay systems or ad-hoc networks in which base stations and relay stations are connected wirelessly in that distributed antenna units are connected via wired or dedicated circuits. Ru. Furthermore, it is also distinguished from repeaters that merely amplify and transmit signals, in that each of the distributed antennas can transmit different signals to respective terminals adjacent to the antennas based on a base station command.

  The distributed antenna system according to one aspect shown in FIG. 1 includes a DAS unit and a DAS controller 10.

  The DAS unit is any one of a headend unit (Headend Unit) 20, a hub unit (Hub Unit) 30, and a radio unit (Radio Unit) 40, and based on a predetermined traffic transmission policy, the unit's input port Send the traffic received from to the output port.

The headend unit 20 of the distributed antenna system is interfaced with the base station to receive, digitize, frame and transmit various radio signals. In addition, in order to support the backhaul function for the small cell and the Wi-Fi (registered trademark) service, it is possible to perform a function of receiving and framing Ethernet data, and transmitting the data.
When the head end unit 20 performs framing, it adds header information for data transmission, and based on the added header information, compares it with the match field of the traffic transmission policy in the data plane 300. Routing according to the rule found, and transmitting the frame to the destination port. Uplink traffic processing proceeds in the reverse order.

  The head end unit 20 converts an analog radio frequency signal of the radio frequency (RF) band received from the base station into a digital radio frequency signal and distributes the signal to a plurality of output ports. In the embodiment shown in FIG. 1, the head end unit 20 has been exemplarily shown to have two output ports.

The hub unit 30 or the radio unit 40 can be connected to this output port.
After receiving the frame, the hub unit 30 transmits the frame to the destination port based on the frame header information. According to still another aspect of the invention, Ethernet information is extracted from a frame if the destination port is a small cell or an Ethernet port for supporting Wi-Fi service. After that, perform the switching function. Uplink traffic processing proceeds in the reverse order.

  After receiving the frame, the radio unit 40 converts and sends the frame to an RF signal based on the frame header information, transmits the frame to the destination port (for Daisy Chain), or the destination port is small. When the Ethernet port is for supporting a cell or Wi-Fi (registered trademark) service, the Ethernet (registered trademark) information is extracted from the frame and then the Wi-Fi (registered trademark) AP or Perform the function of transmitting to a small cell. Uplink traffic processing proceeds in the reverse order.

  The DAS controller 10 creates or changes the traffic transmission policy with the open flow controller, and uses the open flow protocol so that the DAS unit (HEU, HU, RU) can apply the policy to the forwarding table of the data plane 300, Transmit to unit.

The DAS controller 10 is responsible for managing and controlling the traffic transmission policy of the distributed antenna system unit using an open flow protocol, managing the unit and the port status of the unit, and managing the port-based statistical information. In particular, the DAS controller 10 can provide a function capable of variously controlling traffic transmission policies based on status information and statistical information, or by operator settings.
The DAS controller 10 may be integrated with a management system of the distributed antenna system and operated to operate in a separate system.

  As shown in FIG. 1, the Wi-Fi (registered trademark) AP and the small cell are dynamically linked to the hub unit 30 and the radio unit 40 for backhaul service according to the installation environment and user requirements. It can be configured.

  As the number of Wi-Fi (registered trademark) APs and small cells to be installed increases and the number of users increases, congestion of backhaul service provided from the distributed antenna system only occurs. of Service Processing can be provided through metering capabilities provided by OpenFlow to improve service efficiency.

  FIG. 2 is a view showing a frame structure used in the distributed antenna system shown in FIG.

  Referring to FIG. 2, each system unit (HEU, HU, RU) of the distributed antenna system frames and transmits received data for fronthaul and backhaul services. At this time, one frame includes a frame header and frame data.

  The frame header is a part including information on features of the frame, and may include a destination tag, a source tag, and vendor specific information.

Here, the destination tag is a tag that can be identified on the network that specifies the final destination of the frame, and if mapped to Ethernet (registered trademark), the destination Ethernet (registered trademark) address (destination Ethernet It plays a role as registered trademark) address).
Also, a source tag is a tag that can be identified on the network that specifies the generation location of the frame, and if mapped to Ethernet (registered trademark), a source Ethernet (registered trademark) address (source Ethernet (registered trademark)) play a role like address). The source tag is a tag indicating the sender, and is not a necessary element, and can be omitted in some cases.
Also, the vendor specific information is used as an application for a special function provided by the vendor, and includes information that can be further configured by a system administrator.

  The functionality of a typical distributed antenna system to transmit the frame to various destinations using a destination tag value similar to the destination Ethernet address as the transmission address of the frame was included in the header Of the various fields, after classifying the frame as a part of the match field, it is the same as the open flow support function that takes various actions (for example, transmit the frame to a specific output port). Therefore, in the software defined network, data of each unit of the distributed antenna system actually processing data, using the open flow protocol which is a protocol used as a construction technique for the control plane of each unit of the distributed antenna system. The plane 300 can support vendor's own standard frame routing using the form as shown in FIG. 2, and the frame header may also be used when using a standard generic header such as an Ethernet (registered trademark) header. There is a usable effect without changing the control plane 200.

  FIG. 3 is a block diagram illustrating the configuration of a distributed antenna system unit according to one embodiment.

  FIG. 3 illustrates the module structure of each unit of the distributed antenna system using the traffic transmission function using the open flow protocol shown in FIG.

  The DAS controller 10 is an open flow controller, and may include a DAS unit transmission policy management module 100, a DAS unit and port state management module 110, and a DAS unit statistical information management module 120. The DAS controller 10 manages the traffic transmission policy for DAS units (HEU, HU, RU) using the open flow protocol, the unit for managing units and unit port states, and the DAS unit statistical information. Function and can.

  If DAS unit transmission policy management module 100 needs to change traffic transmission policy through an operation of an operator or application of an external upper network management system (northbound network management system) existing for integrated management of software defined network, Request open traffic protocol change from each DAS unit using open flow protocol. Also, the DAS unit transmission policy management module 100 dynamically changes the traffic transmission policy according to the state event transmitted from each DAS unit through the DAS unit and port state management module 110, and the DAS unit statistical information management module 120 Traffic transmission policies can be dynamically generated or changed based on statistical information from each combined DAS unit.

  The DAS unit and port state management module 110 is capable of receiving the change event from the DAS unit and managing the port state of the DAS unit if the port state of the DAS unit is changed through the control message provided by the open flow protocol And periodically exchange status management messages with the DAS unit to check and manage the status of the DAS unit itself. As described above, the DAS unit transmission policy management module 100 can dynamically change the traffic transmission policy according to the state of the DAS unit and the unit and port managed by the port state management module 110.

  The DAS unit statistical information management module 120 can periodically monitor the current resource usage state of each DAS unit using various port and unit statistical functions provided by the open flow protocol. As described above, the DAS unit transmission policy management module 100 may dynamically generate or change the traffic transmission policy based on statistical information from each DAS unit integrated from the DAS unit statistical information management module 120. it can.

The DAS unit corresponds to any one of the head end unit 20, the hub unit 30, and the radio unit 40. Each DAS unit is separated into a control plane 200 and a data plane 300. The control plane 200 can process the signals flowing into the DAS unit and construct and store control information necessary for transmission. Data plane 300 may perform functions to receive, frame, and route signals flowing into DAS units.
The control plane 200 of the DAS unit interlocks with the open flow controller DAS controller 10 using the open flow protocol, and the transmission policy control module 210, the state management module 220, the statistical processing module 230, and the matching hierarchy as a service module. And the like (mediation layer) 240.

  The transmission policy control module 210 may receive an addition, deletion, or change event to traffic transmission policy information from the DAS controller 10 to change the information of the data plane 300.

  That is, the DAS unit receives the traffic transmission policy from the DAS controller 10 and updates the forwarding table of the data plane 300 in which the traffic transmission policy information is stored.

  Also, the DAS unit can receive the service classification policy and the framing policy generated or changed by the DAS controller 10, and can update the mapping table of the service data plane 300 in which the service mapping information and the framing information are stored. .

At this time, the traffic transmission policy to be changed is Ethernet (registered trademark) for radio traffic or backhaul function support for small cells and Wi-Fi (registered trademark) in order to support the front hall function for the macro radio base station. ) It can be a policy applied to traffic.
For policies applied to Ethernet traffic, there are many more configurations possible than those applied to radio traffic. This is because the Ethernet (registered trademark) header has more various information. The conditions applicable to the open flow are variously applicable from the physical port number to the TCP / UDP port number of the OSI layer 4. Such conditions can be used to determine the frame transmission method for Ethernet traffic.
The state management module 220 periodically exchanges state information with the DAS controller 10 to manage each other's state and to transmit the event to the DAS controller 10 when the port state in the unit is changed. I do.

That is, the DAS controller 10 receives unit status information from the DAS unit status management module 220 at a set cycle, and dynamically reflects the unit status information when changing the unit status information, thereby changing the traffic transmission policy. The modified policy may be transmitted to the DAS unit again using the open flow protocol. At this time, the operator can set an optimum time according to the network operation policy and the network characteristics as the cycle of exchanging unit state information.
Also, the state management module 220 of the DAS unit transmits port state change information in the unit to the DAS controller 10, and the DAS controller 10 dynamically transmits traffic reflecting the port state change information of the received unit. The policy may be changed, and the changed policy may be transmitted to the DAS unit again.

  The statistical processing module 230 may collect traffic statistics for each port processed from the data plane 300 periodically and report the traffic statistics to the DAS controller 10. The DAS controller 10 can dynamically generate or change traffic transmission policies based on statistics for each unit, statistics for each port, and the like.

  In addition, the operator requests traffic transmission policy change to the DAS controller 10 based on the collected statistical information, and transmits traffic via an external upper network management system application or the like for integrated management of the software defined network. Policy changes can be requested to the DAS controller 10.

  The alignment hierarchy 240 also works together if the data plane 300 of the DAS unit does not support the open flow protocol, but only the functionality of the vendor itself standard. The alignment layer 240 may perform mapping and linkage with vendor policy based on open flow protocol information. As an example, the matching hierarchy 240 may use vendor-specific standards in the data plane 300 of the DAS unit, and the upper control plane 200 may use open flow standards.

  That is, if the data plane 300 of the DAS unit provides only the traffic transmission function of the vendor's own standard, the matching hierarchy 240 maps the open flow based traffic transmission policy with the traffic transmission policy of the DAS unit's own standard. It can be set.

The data plane 300 of the DAS unit is responsible for processing data and may include a traffic routing function 310 and a statistical processing function 320 as server modules.
The traffic routing function 310 functions to transmit the traffic received from the input port to the output port based on the information set by the control plane 200. Support N to M routing function to support various forms of traffic transmission.
Traffic routing is performed by a forwarding table set in the data plane 300, which is updated through the transmission policy control module 210 of the control plane 200 at the request of the DAS controller 10 through the open flow protocol.

  The forwarding table may include a flow table (Flow Table), a group table (Group Table), and a meter table (Meter Table).

  The flow table is configured to include information such as conditions (match fields), actions (actions) and statistics (counters), and is set if specific traffic matches the conditions of specific entries in the flow table. It is a table that stores information to execute processing.

  The group table is a table configured to execute a series of processes for specific traffic. When the processing information of the flow table is a group ID which is entry information of the group table, the processing information of action buckets stored in the group table is sequentially performed. The group table is composed of a group ID, a group type, statistics, and action buckets, and the group type determines whether or not to execute all action buckets processing.

  Meter tables are provided to enable open flow and simple QoS in various ways. As an example, a method is used to measure the traffic bandwidth of a particular port and adjust that bandwidth.

  The statistical processing function 320 records various statistical information on traffic received from the input port and traffic transmitted to the output port. It also provides the ability to transmit such information so that the statistical processing module 230 of the control plane 200 can use it.

  FIG. 4 is a view illustrating a process of setting a data plane 300 of a distributed antenna system unit not supporting an open flow protocol according to another embodiment.

  Referring to FIG. 4, as one example, the OpenFlow controller is used for the purpose of “match field is intended, for example, through an application of an external high-level network management system existing for operator operation or integrated management of software defined network. If it is instructed to change the traffic transmission policy that the destination tag 10 is converted to the Ethernet (registered trademark) destination address and transmit the frame, the policy is transmitted to the DAS unit. .

  The control plane 200 of the DAS unit processes the traffic transmission policy received from the open flow controller and transmits it to the matching hierarchy 240.

  The matching hierarchy 240 operates differently depending on whether it supports the open flow protocol of the data plane 300 or only the vendor itself. As shown in FIG. 4, the data plane 300 does not support routing through the Ethernet destination address if supporting only the vendor's own standard, so the destination tag is matched to the vendor's own standard. It is held, changed to route the frame to the destination, and transmitted to the data plane 300.

  The data plane 300 reflects the received traffic transmission policy in the flow table and updates the flow table. As an example, the open flow protocol has requested that the destination tag be changed to an Ethernet destination address, but since the data plane 300 does not support the open flow protocol, unlike the request, the vendor's own standard It is changed to hold the destination tag according to and updated in the flow table.

  FIG. 5 is a view showing a distributed antenna system policy setting process using an open flow protocol according to still another embodiment.

  According to one aspect, the open flow based distributed antenna system policy setting method comprises the steps of: the DAS controller 10 receiving a new policy setting request from the operator terminal or the integrated software definition network support application; The request is processed with the new policy information and transmitted to the DAS unit using the open flow protocol, the DAS unit receives the new policy information, and the DAS unit receives the received policy information. The steps of mapping with configuration information conforming to the data plane 300 structure, and updating the forwarding table with the mapped configuration information by the DAS unit, are included.

  According to still another aspect, the policy information updated in the open flow-based distributed antenna system policy setting method may include radio traffic transmission policy information or Ethernet traffic transmission policy.

  According to still another aspect, the open flow-based distributed antenna system policy setting method may further include the step of the DAS unit updating the service classification policy and the framing policy with the mapped setting information.

  Referring to FIG. 5, (1) DAS controller 10, that is, an open flow controller, inputs new policy information through an operator's command line interface (CLI) or web interface (web interface). The OpenFlow controller processes the policy information and sends the policy to the related DAS unit if it receives it from the external upper network management system application that exists for integrated management of the software defined network or Communicate information. In the example shown in FIG. 5, the open flow controller transmits the policy information to the head end unit A, the hub unit B, and the radio unit C, respectively.

  (2) The open flow channel of the control plane 200 of the DAS unit receives policy information from the open flow controller using the open flow protocol, and transmits the received policy information to the matching layer 240.

  (3) The matching hierarchy 240 of the control plane 200 of the DAS unit performs the process of mapping the policy information of the open flow protocol to the structure of the lower data plane 300. At this time, if the data plane 300 supports the open flow protocol, the received policy information is updated as it is, the forwarding table is updated, and the open flow protocol is not supported. Map and update the forwarding table. The information updated in the forwarding table becomes information for traffic routing.

(4) If the DAS unit is a unit that performs framing or deframing on the received traffic, such as the head end unit 20 or the radio unit 40, for service classification and framing Update the policy information in the data plane 300 to the service mapping and framing table.
The services provided by the distributed antenna system can be classified into macro fronthaul service and small cell / Wi-Fi (registered trademark) backhaul service.

  Macro front hall service mainly integrates one or more macro radio base station signals (CDMA, GSM (registered trademark), WCDMA (registered trademark), LTE, LTE-A, etc.) and is located at a long distance radio A service that transmits to unit 40 or provides transmission in the opposite direction. That is, the head end unit 20 receives RF signals of various operators, CPRI (Common Public Radio Interface) frames, and transmits them to a plurality of radio units 40. At this time, transmission of the RF signal or CPRI frame uses the transmission network of the distributed antenna system itself, the radio unit 40 restores the RF signal to the original signal, converts the CRPR frame to the RF signal, and transmits it wirelessly Do.

  Small cell / Wi-Fi (registered trademark) backhaul service uses Ethernet network of distributed antenna system to support Ethernet packets in small cell and Wi-Fi (registered trademark) service support. A service that transmits to the Wi-Fi (registered trademark) AP or small cell connected to the hub unit 30 or the radio unit 40 or in the opposite direction is a service.

  Framing is to generate a frame composed of frame data for converting received traffic into data, a destination tag, a source tag, and a frame header including vendor specific information, and deframe processing is performed for the destination tag. It is to remove the frame header from the destination and extract frame data.

  According to an additional aspect, the DAS controller 10 may dynamically change the traffic transmission policy and transmit it to the DAS unit according to the state of the DAS unit and the port state of the DAS unit.

  That is, in the OpenFlow-based distributed antenna system policy setting method, the DAS controller 10 receives the state information of the DAS unit in a set cycle, and the DAS controller 10 reflects the received state information. Changing the traffic transmission policy, and transmitting the changed policy to the DAS unit.

  Also, in the open flow based distributed antenna system policy setting method, the DAS unit transmits the changed port state information to the DAS controller 10, and the DAS controller 10 reflects the port state of the received DAS unit. Changing the traffic transmission policy, and transmitting the changed policy to the DAS unit.

  FIG. 6 is a view showing an example of traffic transmission of a distributed antenna system according to another embodiment, and FIG. 7 is an example of configured policy information of the distributed antenna system unit for the traffic transmission shown in FIG. FIG.

  A traffic routing method of an open flow based distributed antenna system according to one aspect includes the steps of: a DAS unit extracting a matching field from header information of a received frame; and the DAS unit matching a forwarding table in the extracted matching field Routing according to the traffic transmission policy to be matched and sending the frame to the output port as compared to the rules.

  According to yet another aspect, the traffic transmission policy of the open flow based distributed antenna system may include a method of routing based on traffic routing policy supporting policies applied to radio traffic or Ethernet traffic. .

  According to yet another aspect, a traffic routing method of an open flow based distributed antenna system classifies and classifies services of traffic received from an input port before the DAS unit extracts a matching field. It may further include the step of framing by the selected service.

  According to yet another aspect, the traffic routing method of the open flow based distributed antenna system may further include the step of deframeting the DAS unit before sending the frame to the output port.

  Through the process shown in FIG. 5, it is assumed that policy information of the DAS unit is set as shown in the table of FIG.

  An example of traffic transmission in the downlink direction of the distributed antenna system will be described with reference to FIGS. 6 and 7.

  First, a setting example of policy information of each unit will be described with reference to FIG. The head end unit A is a unit that performs framing, and policy information of the head end unit A is stored in a service mapping and framing table and a forwarding table. The service mapping and framing table and the forwarding table both include a condition (match rule) and an action (action), and in the example of FIG. 7, it is composed of two entries.

  Looking at the service mapping and framing table of the head end unit A in FIG. 7, the service of the received traffic is classified, and if the service matches the service A, the destination tag is X and the frame header Is configured to add a frame header when the destination tag is Y, if it matches with Service B.

  Referring to the forwarding table of the head end unit A of FIG. 7, when the destination tag of the frame header of the received frame is matched with X, the frame is transmitted to the output port No. 4 and the destination tag When matched with Y, the frame is transmitted to the output port No. 5.

  The hub unit B is a unit that does not perform framing, and policy information of the hub unit B is stored in the forwarding table. The forwarding table of the hub unit B also includes conditions and measures, and in the example of FIG. 7, is configured of two entries.

  Looking at the forwarding table of hub unit B in FIG. 7, when the input port of the received frame is No. 1 and the destination tag of the frame header is matched with X, the frame is set to output port No. 3. When the input port of the transmitted and received frame is No. 1 and the destination tag is matched with Y, the frame is transmitted to the output port No. 3.

  The radio unit C is deframed in the unit that performs framing and in the downlink, so only the policy information stored in the forwarding table is shown. The forwarding table of the radio unit C also includes conditions and measures, and in the example of FIG. 7, is configured of two entries.

  Looking at the forwarding table of radio unit C in FIG. 7, if the input port of the received frame is No. 1 and the destination tag of the frame header is matched with X, then the frame is made output port No. 2 When the input port of the transmitted and received frame is No. 1 and the destination tag is matched with Y, the frame is transmitted to the output port No. 3.

  Referring to FIG. 6 based on the configuration of the table shown in FIG. 7, first, the head end unit A receives an RF signal corresponding to Service A from the macro base station through port number 1. The RF signal received from FIG. 6 is labeled box # 1.

  Service mapping and framing are performed on the data plane 300 of the head end unit A. Therefore, the service of the received RF signal and the service to be mapped are searched for in the condition of the service mapping and framing table. According to the table of FIG. 7, since it is matched with Service A of the first entry, the received RF signal is framed, and the destination tag of the frame header is framed with X. At this time, although the source tag and the vendor specific information are both included in the frame header, they are omitted in the description of the routing process.

  After framing the received RF signal, the data plane 300 of the headend unit A looks for a match condition in the forwarding table using the destination tag value of the frame header. According to FIGS. 6 and 7, since the destination tag of the frame is composed of X, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port 4 as the value stored in the procedure.

  The data plane 300 of the hub unit B searches the forwarding table for matching conditions using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 6 and 7, since the input port of the received frame is port 1 and the destination tag of the frame is X, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port number 3 as the value stored in the procedure.

  The data plane 300 of the radio unit C searches the forwarding table for matching conditions using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 6 and 7, since the input port of the received frame is port 1 and the destination tag of the frame is X, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port 2 as the value stored in the procedure.

  Moreover, the box 2 RF signal which is another example of a downlink is also demonstrated. The head end unit A receives an RF signal corresponding to Service B from the macro base station through port number 2. The RF signal received from FIG. 6 is labeled box # 2.

  Service mapping and framing are performed on the data plane 300 of the head end unit A. Therefore, the service of the received RF signal and the service to be mapped are searched for in the condition of the service mapping and framing table. According to the table of FIG. 7, since it is matched with Service B of the second entry, the received RF signal is framed, and the destination tag of the frame header is framed with Y.

  After framing the received RF signal, the data plane 300 of the headend unit A looks for a match condition in the forwarding table using the destination tag value of the frame header. According to FIGS. 6 and 7, since the destination tag of the frame is configured as Y, it is matched with the second entry of the forwarding table. Therefore, the data plane 300 transmits the frame to the output port No. 5 as a value stored in the procedure.

  The data plane 300 of the hub unit B searches the forwarding table for matching conditions using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 6 and 7, since the input port of the received frame is port 1 and the destination tag of the frame is Y, it is matched with the second entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port number 3 as the value stored in the procedure.

  The data plane 300 of the radio unit C searches the forwarding table for matching conditions using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 6 and 7, since the input port of the received frame is port 1 and the destination tag of the frame is Y, it is matched with the second entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port number 3 as the value stored in the procedure.

  FIG. 8 is a view showing an example of a policy change of a distributed antenna system according to still another embodiment and traffic transmission according to the same, and FIG. 9 is a distributed antenna system unit for the policy change and traffic transmission shown in FIG. It is a table showing an example of set policy information.

  Through the process shown in FIG. 5, as shown in the table in FIG. 7, the policy information of the set DAS unit is no longer required for the radio unit C for Service B, but is required for the radio unit E. Suppose that the policy has been changed.

  Referring to FIGS. 8 and 9, an example will be described in which traffic transmission in the downlink direction of the distributed antenna system is different from the traffic transmission in FIGS.

  First, a setting example of policy information of each unit will be described with reference to FIG. The head end unit A is a unit that performs framing, and policy information of the head end unit A is stored in a service mapping and framing table and a forwarding table. Both the service mapping and framing table and the forwarding table include conditions and measures, and in the example of FIG. 9, as in the case of FIG. 7, two entries are configured.

  Looking at the service mapping and framing table of the head end unit A in FIG. 9, the service of the received traffic is classified, and if the service is matched with the service A, the destination tag is X and the frame header Is configured to add a frame header when the destination tag is Y, if it matches with Service B.

  Referring to the forwarding table of the head end unit A of FIG. 9, when the destination tag of the frame header of the received frame is matched with X, the frame is transmitted to the output port No. 4 and the destination tag When matched with Y, the frame is transmitted to the output port No. 6.

  The hub unit B is a unit that does not perform framing, and policy information of the hub unit B is stored in the forwarding table. The forwarding table of the hub unit B also includes conditions and measures, and unlike the example of FIG. 7, is configured of one entry.

  Looking at the forwarding table of hub unit B in FIG. 9, if the input port of the received frame is No. 1 and the destination tag of the frame header is matched with X, then the frame will be output port No. 3 It is configured to transmit. And unlike the example of FIG. 7, the match condition of the destination tag Y is deleted. This is because the radio unit C connected to the hub unit B no longer needs Service B, so it is deleted in the table under policy control of the open flow controller.

  The radio unit C is deframed in the unit that performs framing and in the downlink, so only the policy information stored in the forwarding table is shown. The forwarding table of the radio unit C also includes conditions and measures, and unlike the example of FIG. 7, is configured of one entry.

Referring to the forwarding table of the radio unit C in FIG. 9, when the input port of the received frame is No. 1 and the destination tag of the frame header is matched with X, the frame is set to the output port No. 2. It is configured to transmit. And unlike the example of FIG. 7, the match condition of the destination tag Y is deleted. This is because the radio unit C connected to the hub unit B no longer needs Service B, so it is deleted in the table under policy control of the open flow controller.
The hub unit D is a unit that does not perform framing, and policy information of the hub unit D is stored in the forwarding table. The forwarding table of the hub unit D also includes conditions and measures, and in the example of FIG. 9, is configured of one entry.

  According to the forwarding table of the hub unit D in FIG. 9, if the input port of the received frame is No. 1 and the destination tag of the frame header is matched with Y, the frame is output port No. 3 It is configured to transmit. And unlike the example of FIG. 7, the match condition of the destination tag Y is added to the hub unit D. This is added to the table under policy control of the open flow controller in order to require the service B in the radio unit E connected to the hub unit D.

  The radio unit E deframes in the unit that performs framing and in the downlink, so only the policy information stored in the forwarding table is shown. The forwarding table of the radio unit E also includes conditions and measures, and in the example of FIG. 9, is configured of one entry.

  According to the forwarding table of the radio unit E in FIG. 9, when the input port of the received frame is No. 1 and the destination tag of the frame header is matched with Y, the frame is set to the output port No. 3. It is configured to transmit. And unlike the example of FIG. 7, the match condition of the destination tag Y is added to the radio unit D. This is added to the table under policy control of the open flow controller in order to require the service B in the radio unit E.

  Referring to FIG. 8 based on the configuration of the table shown in FIG. 9, first, the head end unit A receives an RF signal corresponding to Service A from the macro base station through port number 1. The RF signal received from FIG. 8 is labeled box # 1.

  Service mapping and framing are performed on the data plane 300 of the head end unit A. Therefore, the service of the received RF signal and the service to be mapped are searched for in the condition of the service mapping and framing table. According to the table of FIG. 9, since it is matched with Service A of the first entry, the received RF signal is framed, and the destination tag of the frame header is framed with X. At this time, although the source tag and the vendor specific information are both included in the frame header, they are omitted in the description of the routing process.

  After framing the received RF signal, the data plane 300 of the headend unit A looks for a match condition in the forwarding table using the destination tag value of the frame header. According to FIGS. 8 and 9, since the destination tag of the frame is composed of X, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port 4 as the value stored in the procedure.

  The data plane 300 of the hub unit B searches the forwarding table for matching conditions using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 8 and 9, since the input port of the received frame is port 1 and the destination tag of the frame is X, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port number 3 as the value stored in the procedure.

  The data plane 300 of the radio unit C searches the forwarding table for matching conditions using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 8 and 9, since the input port of the received frame is port 1 and the destination tag of the frame is X, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port 2 as the value stored in the procedure.

  Moreover, the box 2 RF signal which is another example of a downlink is also demonstrated. The head end unit A receives an RF signal corresponding to Service B from the macro base station through port number 2. The RF signal received from FIG. 8 is labeled box # 2.

  Service mapping and framing are performed on the data plane 300 of the head end unit A. Therefore, the service of the received RF signal and the service to be mapped are searched for in the condition of the service mapping and framing table. According to the table of FIG. 9, since it is matched with Service B of the second entry, the received RF signal is framed, and the destination tag of the frame header is framed with Y.

  After framing the received RF signal, the data plane 300 of the headend unit A looks for a match condition in the forwarding table using the destination tag value of the frame header. According to FIGS. 8 and 9, since the destination tag of the frame is configured as Y, it is matched with the second entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port 6 as a value stored in the procedure.

  The data plane 300 of the hub unit D uses the input port number of the received frame and the destination tag value of the frame header as keywords to search for a matching condition in the forwarding table. According to FIGS. 8 and 9, since the input port of the received frame is port 1 and the destination tag of the frame is Y, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port number 3 as the value stored in the procedure.

  The data plane 300 of the radio unit E looks for a matching condition in the forwarding table, using the input port number of the received frame and the destination tag value of the frame header as keywords. According to FIGS. 8 and 9, since the input port of the received frame is port 1 and the destination tag of the frame is Y, it is matched with the first entry of the forwarding table. Thus, the data plane 300 transmits the frame to output port number 3 as the value stored in the procedure.

  Although not shown in FIGS. 6 to 9, the process of transmitting traffic can be divided into two types of patterns. The first pattern is the case where the forwarding table for processing the frame is set in the data plane 300 of each DAS unit, and transmission is possible according to a defined measure, and the second pattern is the data plane of each DAS unit If the forwarding table for processing the frame is not set in 300, the DAS unit temporarily stores the frame in a buffer, queries the controller for a suitable routing policy, and the controller establishes a suitable routing policy. Then, it instructs to be able to update the forwarding table, and if the DAS unit updates the forwarding table, it transmits the frame stored in the buffer according to a defined action. As yet another example in this case, the frame can be discarded.

  Although the present invention has been described above through the embodiments with reference to the attached drawings, the present invention is not limited thereto, and analysis is intended to encompass various modifications that can be derived by those skilled in the art. It must be done. The claims are intended to cover such variations.

  The present invention is applicable to the technical field related to an open flow based distributed antenna system.

10 DAS controller 100 DAS unit transmission policy management module 110 DAS unit and port status management module 120 DAS unit statistical information management module 20 head end unit 30 hub unit 40 radio unit 200 control plane 210 transmission policy control module 220 status management module 230 statistical processing Module 240 Alignment Hierarchy 300 Data Plane 310 Traffic Routing Function 320 Statistics Processing Function

Claims (17)

A DAS unit that sends traffic received from an input port to an output port based on configured traffic transmission policy information;
An open flow-based distributed antenna system including: a DAS controller that generates or changes traffic transmission policies and transmits the policies to DAS units using an open flow protocol.   The open flow based distributed antenna system according to claim 1, wherein the DAS unit is any one of a head end unit, a hub unit and a radio unit.   The open flow-based distributed antenna system according to claim 1, wherein the DAS unit receives the traffic transmission policy from the DAS controller and updates a forwarding table in which the traffic transmission policy information is stored.   The open flow-based distributed antenna system according to claim 1, wherein the traffic transmission policy is a policy applied to radio traffic or Ethernet (registered trademark) traffic.   The open flow infrastructure according to claim 1, wherein the DAS unit receives a service classification policy and a framing policy generated or changed by the DAS controller, and updates a service mapping table in which the service mapping information and the framing information are stored. Distributed antenna system.   The DAS controller receives unit status information from the DAS unit at a set cycle, changes traffic transmission policy at the time of status information change, and transmits the changed policy to the DAS unit using an open flow protocol. The open flow based distributed antenna system described in 1. The DAS unit transmits port state change information in the unit to the DAS controller,
The open flow-based distributed antenna system according to claim 1, wherein the DAS controller changes traffic transmission policy by reflecting port state change information of the received unit, and transmits the changed policy to the DAS unit.   The open flow-based distributed antenna system according to claim 1, wherein the DAS unit maps and sets an open flow-based traffic transmission policy with a traffic transmission policy of a DAS unit vendor standard. The DAS controller receives a new policy setting request from the operator terminal or the integrated software defined network support application;
The DAS controller processing the request with new policy information and transmitting it to the DAS unit using the open flow protocol;
The DAS unit receives new policy information;
Mapping the received policy information with configuration information that matches the data plane structure of the DAS unit;
An open flow-based distributed antenna system policy setting method, comprising: a DAS unit updating a forwarding table with mapped setting information.   The open flow-based distributed antenna system policy setting method according to claim 9, wherein the policy information includes radio traffic transmission policy information or Ethernet (registered trademark) traffic transmission policy.   The OpenFlow-based distributed antenna system policy configuration method of claim 9, further comprising: updating a service classification policy and a framing policy with the mapped configuration information by the DAS unit. The DAS controller receives the state information of the DAS unit at a set cycle;
10. The open flow-based distributed antenna system according to claim 9, further comprising the step of: the DAS controller reflecting the received status information, changing the traffic transmission policy, and transmitting the changed policy to the DAS unit. Policy setting method. The DAS unit transmitting the changed port state information to the DAS controller;
10. The open flow infrastructure according to claim 9, further comprising the step of the DAS controller changing the traffic transmission policy to reflect the port status of the received DAS unit, and transmitting the modified policy to the DAS unit. Distributed antenna system policy setting method. The DAS unit extracting a matching field from header information of the received frame;
The DAS unit routing according to the traffic transmission policy to be matched, compared with the matching rule of the forwarding table in the extracted matching field, and sending out the frame to the output port; Routing method.   The open flow-based distributed antenna system traffic routing method according to claim 14, wherein the traffic transmission policy is a policy applied to radio traffic or Ethernet (registered trademark) traffic.   The OpenFlow-based distribution according to claim 14, further comprising the step of the DAS unit classifying the service of the traffic received from the input port and framing it by the classified service before the step of extracting the matching field. Antenna system traffic routing method.   The OpenFlow-based distributed antenna system traffic routing method according to claim 14, further comprising the step of deframeting the DAS unit before sending the frame to the output port.

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